Re: Rear fender
No reason to have to "tilt the engine". The engines mount in front of the seat tube so the fender doesn't effect engine position.I run rear fenders on my bikes because I don't like that streak up my back when there's water on the road and I don't want it sprayed into the carburetor.
We always suggest removing the front fenders or reinforcing the mounting on them due to several accidents where the fender broke loose and wrapped around the front wheel.
As for drive chain clearance, yes most rear fenders will need to be trimmed to allow the chain to clear but that's a small job with a good set of sheetmetal shears.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"